Ambrinols belong to the class of decaline derivatives of generic formula ##STR3## possessing a double bond in position .alpha., .beta. or .gamma. as indicated by the dotted lines.
They possess interesting odoriferous properties [Arno Muller, International Riechstoff-Kodex, Dr. A. Huthig Verlag, Heidelberg, West-Germany] and consequently have been used advantageously in the manufacture of perfume compositions wherein they develop an olfactive note of amber type; however, in despite of their interest, their utilization sofar has not been extensive. This was eminently due to the poor availability of this class of compounds, the known synthesis for their preparation being rather uneconomical [see e.g. Helv. Chim. Acta, 42, 2233 (1959)]. It is not surprising therefore to observe the constant effort displayed by the whole industry in an attempt to achieve a more economical process for their preparation. The present invention provides an original and useful solution to this problem. Indeed, the process of the invention has the advantage of using, as starting materials, cheaply available products and of enabling the preparation of .alpha.-ambrinol with a defined preferential steric arrangement, the OH group being in the axial position [see. G. Ohloff, Chemie der Geruchs- und Geschmacksstoffe, in Fortschritte der chemischen Forschung, vol. 12, page 188 (1969)].